import re
a='''
<div class="p-name p-name-type-2">
<a href="//item.jd.com/3668211.html" onclick="searchlog(1, '3668211','0','1','','flagsClk=2097626');" target="_blank" title="1900M升级易展mesh分布路由，双千兆，一键互联，全屋信号满格！点击抢购(此商品不参加上述活动)">
<em>TP-LINK TL-WDR5620 1200M 5G双频智能无线<font class="skcolor_ljg">路由器</font> 四天线智能wifi 稳定穿墙高速家用<font class="skcolor_ljg">路由器</font></em>
<i class="promo-words" id="J_AD_3668211">1900M升级易展mesh分布路由，双千兆，一键互联，全屋信号满格！点击抢购(此商品不参加上述活动)</i>
</a>
</div>
'''
str=re.findall('<i class="promo-words" id="J_AD_3668211">(.*?)</i>',a)
print(str)
str=re.findall('<em>(.*?)<font class=".*">(.*?)</font> (.*?)<font class=".*">(.*?)</font></em>',a,re.S)
print(str)
str=re.findall('<a href="//item.jd.com/3668211.html" onclick="searchlog.*;" target="_blank" title="(.*?)">',a)
print(str)
str=re.findall('<a href="//item.jd.com/3668211.html" onclick="searchlog.*;" target="_blank" title="(.*?)">.*?<em>(.*?)<font class=".*">(.*?)</font> (.*?)<font class=".*">(.*?)</font></em>.*?<i class="promo-words" id="J_AD_3668211">(.*?)</i>.*?</a>',a,re.S)
print(str)